I’ll echo the comment about the TO-92 transistors: those close pads are ok for automated soldering, but so easy to get a short when hand soldering. My experience says use a good spacing, and have decent sized pads… easier to get to with your soldering iron. If I remember right, I took a standard ‘widely spaced’ TO-92 footprint, then made the pads even wider (= more oval) to help with the soldering.
To connect ‘external things’ I use something like the ‘Connector PinHeader_1x05_P2.54mm_Vertical’… that’s a ‘5 pin molex’… so you can fit various pins, or just solder wires to it. There’s footprints from 1 up to 40 ways, and 1 or 2 rows
Thanks for asking. I think I did get all the nets sorted but I still don’t understand them. At this point my schematic passes the ERC no problem. My pcb has a raft of errors, such as hole clearance violations, front solder mask aperature bridges items with different nets, same error for rear solder mask. And there are about 10 of those errors. I’m not sure what they mean or how to solve them. Or does a board have to be error free to go to production? I am loving all the comments and suggestions and I’m learning a lot.
Thanks everyone
I do have some USB-C connectors that could be used. Bought them for a repair project that I did. Have another repair project that I’m going to use them on as well. But I do have a lot of 5v wall warts.
It means you haven’t laid out the parts well. And there may be errors in the footprints, I’m thinking the ESP32 module is an imported footprint? Maybe it’s better you start another topic with your project attached so that people can look at your layout. This one has strayed a lot from the original question and a clean start is best.
Capital K for kelvin, good to know. Alt key + 234 on the number pad give you Ω. Alt + 230 give you µ. My resitor drawer cabinet is labelled with RKM code but I didn’t realize it was a thing. I have the TO-92s in my inventory. I don’t think I’ve used any vertical resistors but I’ll have to double check that. I agree they look better.
Learn net classes, check. Working my way through the KiCAD getting started website.
Not sure where to put the 10µF capacitor.
Mounting holes added. Should the schematic have a board outline and the mounting holes go in thier respective places?
I also have the barrel jacks in my inventory.
This is the LDR I was planning to use. https://www.amazon.ca/Photoresistor-Photo-Resistors-Dependant-Resistor/dp/B00SWO73DS
I did start to lay this out on some perf board. But then I started learning KiCAD and decided to do a pcb for it.
What equipment would one need to test EMC?
Schematics have no dimensional or layout information. The PCB is a physical realisation of the schematic. As is a breadboard patch-up.
Some people put mounting hole on the schematic so that there’s a symbol corresponding to the hole. It’s also necessary if the hole is plated and wired to say ground. Others just put the holes in the layout only and mark them Not in Schematic so that DRC doesn’t complain.
Below, is a cruelly enlarged part of your PCB. The green arrows show problems with tracks. There are other problems on the PCB.
Many of these problems can be removed with: Tools > Clean up Tracks and Vias. Other problems may reqire you to manually correct. (Click on image to magnify in case you are not familiar with the forum workings).
I stopped doing that on windows 20 years ago. When I switched to Linux some 10 years ago I never bothered to look up what system they have for those weird characters.
To do it properly… Start with a heavily EMC shielded building, then put a specialized lab with expensive equipment in it. And then add some people with specialized knowledge and experience to do such tests. There are few people who can afford such things, but tests are mandatory for all equipment being sold, and most companies hire specialized companies for these tests.
But there are also things like “pre-compliance tests”. Because the tests are expensive, you want to know beforehand whether your product has any chance of passing the tests. Some equipment acessible on a DIY or small company level:
Oscilloscope with the highest bandwidth you can afford.
A real spectrum analyzer. (Preferably up to 6GHz or so)
A set of “near field probes” (these used to be redicilously expensive (several hundred EUR) but are very simple things. The Chinese now make full sets with different sizes for EUR 10 or so. You do need a high bandwidth RF amplifier with these. Near field probes do not do absolute nor accurate measurements, but they can be used to analyze which parts of a PCB are the causes of the biggest EMC issues.
LISN (Line Impedance Stabilization Network) combined with a heavy steel plate as a reference surface.
VNA (Vector Network Analyzer) There have been made a bunch of quite nice analyzers which are affordable for DIY prices (EUR 300 or so).
But as long as you’re not planning to sell products commercially, it not matter all that much. What I do recommend is to read a few books and get information about EMC compatibility (yeah that’s double) from other sources. Youtube video’s about GND planes (such as the Rick Hartley video of 2 hour and 19 minutes) and video’s about how currents behave in electronic circuits made visual with field solvers give you a good idea of what are the important factors. (First most, a full GND plane, second: filtering for everything connecting to the PCB with cables).
Don’t put too much documenatation of the PCB (such as it’s size, footprint position etc) in the schematic. It just creates maintenance headaches an documentation will go out of sync. I am in a habbit of tugging the mounting holes into a corner of the schematic, just to keep them into the same workflow. I never tried to mark them as “not in schematic” as retiredfeline suggests, but that should work to.
You create a schematic drawing by placing symbols on a sheet and connecting those symbols in a certain way with wires.
To then create a PCB, you assign footprints to the symbols manually (because the program has no way of knowing exactly what footprint is needed for each symbol). The program is, however, smart enough to know which pins on which wires are connected to each other. The program is also smart enough to transfer this knowledge to the PCB so the program can assist you to join the pads on the footprints correctly, without you having to constantly refer to the schematic to check. When you start your PCB, the program assistance shows as “Ratlines” joining the pads of the footprints identically to the wires on the schematic.
You then create the PCB by giving it a shape, moving the footprints to suitable locations and replacing the ratlines with tracks.
As an aid to the user, the wires which convert to ratlines, which in turn you convert to tracks, are known as “Nets”, and as a further aid to the user, each net is given its own individual identification.
Various actions can be carried out on nets, either as groups or individually, to make the PCB quicker and easier to design.
Using the old fashioned method allows a basic understanding of Netlist Export/Import.
FROM SCHEMATIC
GOTO → File → Export → Netlist…
TO PRINTED CIRCUIT BOARD
GOTO → File → Import → Netlist…
When dragging a Copper Track it can be temporarily ‘finished’ (Right Click Context Menu)
Mentioning the Right Click Context Menu informs a ‘Newbie’ of additional features.
I just moved my 32ft. Trailer to new property and have spent the last week preparing/installing a new RV Subpanel box 175ft. from Main Service. Only took a few hours after a week preparation.
I lost my internet connection temporarily. Before being able to be more descriptive to your comment. You were offering more expedient methods.
You should certainly set about understanding what they mean and their implications . . . then you can decide if you need to take any actions to address them or not.
The green arrows show problems with tracks. There are other problems on the PCB.
